Pinion gears used to transfer rotary power from a drive motor to a swing gear of a work machine, for example, an excavator, a tree harvester and the like are well known in the art. Such gears are normally mounted on a shaft of the drive motor and engageable with the swing gear to cause rotation of a swing platform pivotally connected to a frame of the work machine.
The position of the pinion gear relative to the swing gear is accurately controlled in order to obtain a desired amount of backlash for maximum gear life and proper operation. Such accurate control is achieved by maintaining tight tolerances and a tight tolerance stack-up between associated parts. This, tends to be expensive to manufacture, takes an excessive amount of manufacturing time, and has a high manufacturing scrap rate.
It has been found that over time the mating gears tend to wear, especially when used in harsh environmental applications. Unless provisions are made for adjustment of the drive pinion relative to the swing gear the drive pinion and swing gear must be replaced. This major overhaul takes much time and requires that the machine is out of service during repairs. As earlier indicated, replacement part cost is extremely high.
In applications where the pinion gear is supported on a cantilevered drive shaft, the potential for premature shaft bearing failure and shaft bending under severe operating loads is high. Since the distal end of the shaft is not supported, radial loads applied to the pinion gear cause side loading of the shaft and a high moment of force. This side loading result in excessive drive motor bearing loading, shaft loading and premature failure of the components.
The present invention is directed to overcoming one or more of the problems as set forth above.